Carburetor



Jung-24, 1930.

L. DE MARCO 1,765,406

CARBURETOR Filed Sept. 8, 1925 2 Sheets-Sheet 1 TNVENTOR. .Kouz's De [fierce x %4? v ATTORN sys June 24, 1930. DE MARCQ 1,765,406

CARBURETOR Filed Sept. 8, 1925 2 Sheets-Sheet 2 INVENTOR.

ouz's 176 [Warao Q?%,M *9 I A TTORN S Patented June 24, 1930 PATENT? OFFICE LOUIS 1m MARCO, or CLEVELAND, OHIO CARBURETOR Application filed September 8, 1925. Serial No. 54,924.

This invention, as has been indicated, re-

lates to an improved type of carburetor. More particularly it comprises a carburetor having a float chamber and a mixingchamher, said float chamber having mechanism for maintaining the liquid level within the mixing chamber, and the mixing chamber having an improved construction for controlling the admission of air adjacent the base of the fuel supply nozzle, and, an improved 'construction of the auxiliary air supply controlling mechanism.

The principal object of the present invention is to improve carburetor construction,particularly for use upon internal combusti'onengines for motor vehicles.

Another object of the invention is to "provide a carburetor which will permit the supply of a very rich mixture for starting '20 purposes, and which will be capable of a simple and delicate adjustmentfor any desired operative condition of said motor.

Another object of the invention is to provide a manual control for the carburetor adjustment at the lower speeds, and an auto-' matic control of the auxiliary air admission at-higher speeds. I t Another object of the invention is to coordinate the throttle or butterflyvalve, and aothe main air supply valve, and to provide for an adjustment between the'same. v

A further object of the invention is to provide an admission port for the liquid fuel supply to the jet nozzle at an'elevated '35: position whereby sediment or foreign matter nism embodying the invention, such disclosed means constltutlng, however,-tbut one of various mechanical forms in which the principleof the invention may be used.

Insaid'annexed drawing:

Fig. 1 is a transverse centrally vertical section showing the float and'mixing chambersand their associated mechanism; Fig.

2 isa horiz'ontalsectional view taken along 3;) the line 22 shown in Fig. 1 looking in the direction of the arrows; Fig. 3 is a detail sectional view showing the needle valve adjustment; Fig. 4 is a side view of the valve control mechanism; Fig. 5 is an end view '60 of the valve control mechanism; and Fig. 6 is a detail view showing the adjustable stops for'the valve control mechanism.

As will be clearly seen in the drawing, the carburetor comprises a cylindrical casing having a flange 2 at its upper end whereby it may be attached in the usual manner to the 'lowerend of the intake manifold of an internal combustion-engine, in accordance with standard practice The intermediate? portion of said casing is provided with an enlarged chamber 3 having upwardly and downwardly inclined walls 4:, 5, respectively.

For convenience of manufacture said casing 1s preferably formed 1n two sectlons;

which are joined adjacent the upper portion of the enlarged chamber by means of screws, or other suitable fastening elements, engaged through apertures "in flanges 7 8, formed about the respective sections of said casing. The lower section 9 of said casing below the enlarged chamber, may be of somewhat greater diameter than the upper portion of'the top section thereof above the enlarged chamber, and at one side thereofii a short lateral extension 11 is provided for the admission ofthe auxiliary air supply for high speeds.

I The bottom of the casing is closedby base plate 12 which is centrally apertured totl provide a central air supply passageway 13 about the fuel nozzle 14. The margin of-said base plate is securely attached to the lower end of a tubular member 15, the upper end of which extends to a position: somewhat below the central portion ofthe enlarged central section of the casing. The upper end of said tubular member is screw "threaded to receive a ring 16. An air valve comprising 'a tubular body iportion'l? and V the casing through the auxiliary air port. The body portion of the air valve is tubular angular flange portion 18 is provided to regulate the quantity of air admitted to in form as stated and is of adiameter slightly greater than that of the ring 16, so as to' permit free movement past said ringin an upward direction. The lower end of the body portion of the air valve is provided with a ring 19 suitably secured to the inner wall thereof, said ring forming the lower abutment of a coil spring 21, the

'upper end of which is adapted to abut agalnst one side of the ring 16. Thus, by' changin the position of the ring 16, the degree of tension upon the coil spring 21- may be regulated, and the time of opening of the auxiliary air valve may be changed so as to respond to any predetermined amount of suction in the intake manifold;

; The angular fiangeof the air valve is adapted to seat against the inclined walls 5 of range of speeds of the motor.

the lar er ortion of the basin and to b p form an air tightclosure during the lower The fuel nozzle is supported upon a fuel V ,supply arm 22 extending laterallyfrom the one side of the float chamber, presently tobe described, toward the central aperture 13 of said base plate. The fuel supply,

"nozzle lt for the carburetor comprises a and is closed by a screw 26. An intervertical jet preferably formed integrally with the fuel supplyzarm, 22 and extends secting; bore 27 is formed through the center of the"fuel supply arm 22 and is closed by a screw 28. The screws 26 and- V '98 may be removed to free the passage-ways. I.

7 from foreignmatter or to flush out the adjacent chambers. V 7 r V The fuel supply nozzle at its enlarged end. is preferably of approximately one-fourth the diameter of the central air supply pas-v sage-way. Between thesubstantially; con-,

. ical base of the fuel supply nozzle and themargins of the aperture in the base plate, an annular passage-wayisthus prov ded for the normal air supply of the carburetor- 1 Adjacent the base of the nozzle there is -provided an annular shoulder 29 against:

which the lower end of the main air supply. controlsleeve 31is adapted to seat. Said .tion of the casing.

upper end of said sleeve as is clearly shown in Fig. 1 of the drawing, comprises a tubular member of somewhat less diameter than that of the stationary tubular member 15, heretofore described and with which it has free sliding engagement. Adjacent the substantially conical upper end of said sleeve a plurality of apertures 32, having upwardly 7 inclined side edges, are provided, through which apertures the vaporized fuel mixture is. discharged into the enlarged central por- The upper end of the tubular sleeve is thus provided with four upwardly inclined supporting members 33,

which at their meetin point are provided vhich a'link 35 is sea pivot pin 86. The link is connected by means of a pivot 37 with an adjustable arm with a pivot 34:, to cured by means of 38, the other end of which is provided with an eye, through which the shaft 39 con nected with the throttle control mechanism is engaged, said arm being held in any desired position of adg'ustment by means'of a set screw ll. Said arm, as is clearly shown in Fig. l of the drawing, is. seated in "an opening 42 formed through the side wall of the upper section of the casing, and is freely movable at its inner end, so as to shift the air control. sleeve upwardly or downwardly: to provideany degree of adgustment-of the main air supply of the carburetor. 'lVhen said sleeve is in its lowermost -pos1t1on, the main air supply w ll be completely out off and the suction of the engine will be ap;;

plied directly to the liquid fuel supply in theupper end of the nozzle.

' The upper end of thecasing is provided with a butterfly valve 43 of the usual type, carried on'a shaft a l. I butterfly va ve 4:3 co-operate with the main air supply sleeve 31 a cam arm 45 is pro.- vided, which is adapted to bear upon a roller terminal 4-6 provided on the outer end of an arm 47, securedto one end of the 6 shaft'of the air valve sleeve. A coil spring elS'is adapted to hold said arm and roller infirm contact with the cam of the butterfly valve shaft. Thus, as the butterfly valve shaft is actuatedthesleevecontrolling; 5

the admission of air through the main air supply passage-way will be correspondingly adjusted. As is shown in Figs. 1 ands: the opening of thefbutterfly valve is accompanied by the on ting off of the main air L supply and increasing the amount of air. drawn through the, auxiliary-air supply passageway.

In addition to the controlling-m echanism above described, the earburetor'is provided with afloat chamberffil. within which apivoted float 52 is mounted, saidffloat acting P against one end of a liquid fuel "control le- 'ver 53, an intermediateIportion' of which operates a plunger valve 54 extending into a In order to have the;

terminal provided on the liquid fuel supply line. The liquid fuel is drawn into the fuel supply nozzle 14 through a passageway 56 provided within the thickened wall portion between the floatchainber and the lower section 9 of the casing, and the bore 27 of the fuel supply arm 22 intersects said passage-way. The passage-way 56 communicates with the float chamber 51 at a point spaced from the base thereof through a lateral opening 57 The base of the float chamher is of funnel-like shape and is provided with a central opening, closed bya screw plug 58, which may be used to remove foreign matter.

An angular extension 59 isformed integrally with the thickened wall portion between the fioat chamber and the lower section of the casing and projects to one side of the carburetor. Said extension is provided with a screw-threaded aperture, adapted to receive the threaded stem of a needle valve 61. The needle valve is provided with a knurled head at its outer end to permit a fine adjustment of the same. The lower end of the needle valve is adapted to co-act with a seat formed in the walls of the passageway 56 between the lateral opening 57 and the bore 27 of the transverse passage-way to the fuel supply arm.

As has been indicated the construction described provides for a rich mixture for starting and for an adequate admission of air as the motor is accelerated. The auxiliary air supply is not brought into action at the lower engine speeds but as the throttle is opened the positively controlled air supply is cut off and the auxiliary air supply is used in proportion to the amount of engine speed developed. However, this adjustment of the relative action of the main and auxiliary air supplies may be so arranged that when the engine is under heavy load, with the throttle quite widely open, both air supplies will function, but a richer mixture will result because of the slower engine speed.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and.

distinctly claim as my invention 1. A carburetor having a vertical mixing chamber a fuel nozzle disposed centrally thereof and having an enlarged tapered base, a stationary sleeve spaced from the upper end of said nozzle, an air cut-off sleeve movablyco-operating with the inner 'wallsof said stationary sleeve, an auxiliary air control sleeve slidably engaged with the exterior walls of said stationary sleeve, manually operable means for controlling the position of" said inner sleeve and spring means for con trolling the position of said external sleeve.

2. A carburetor having a vertical mixing chamber, a hollow nozzle mounted centrally of the base thereof, a stationary cylindrical sleeve spaced from the upper portion of said hollow nozzle and provided with an aperture adjacent the base thereof, a vertically reciprocable sleeve adapted to open or close said aperture adjacent the base" of said nozzle and slidably engaged withinsaid stationary sleeve, means for controlling the flow of liquid to said nozzle, an enlarged housing spaced from the outer walls of said stationary sleeve, an opening adjacent the base of said housing for the admission of air thereto, an upwardly movable air control valve slidably engaged over said stationary sleeve in an enlarged chamber of said housing positioned adjacent the upper end of said fuel supply nozzle, an outwardly projecting flange mounted upon said air control valve and cooperating with the bottom walls of said enlarged chamber, and resilient means for maintaining said valve in normally closed position.

Signed by me this 6th day of August,

LOUIS DE MARCO. 

